I guess it is quite common in Finland. When I was a kid we probably had mashed potatoes at least once a week. And no, I didn't know my grandma had 3 Michelin stars :O
I wouldn't like to eat only mashed potatoes, but I wouldn't like to eat only fried potatoes either. That's the thing with potatoes, they are so versatile. I once had potatoes every day of the week and didn't realize until sunday because each day I had different kinds of potatoes.
As a wise man once said: "Boil em, mash em, stick em in a stew."